In a small measuring cup, combine cocoa and boiling water. Whisk and blend until smooth, and set aside.

In
the bowl of a stand mixer fitted with the paddle beater, combine flour,
Splenda, baking soda and salt. Add butter and mix until the mixture is
crumbly.

In a separate bowl, combine eggs, milk, cocoa mixture
and vanilla. Add 1/3 of this wet mixture to the mixer bowl. Beat on low
speed until every thing is combined, then increase to medium speed and
beat for an additional 30 seconds. Scrape down the bowl, and add
another 1/3 of the wet mixture to the mixer bowl. Repeat, until all of
the wet mixture has been added and the batter is smooth.

Using an ice cream scoop with a release (called a "disher"), or a large spoon, scoop the batter into the cupcake tin.

Bake
18 minutes or until a toothpick inserted in the center comes out clean.
The cupcakes will not be smooth on top, but that's okay. Remove the
cupcakes from the pan onto a wire rack, and let them cool completely.

While the cupcakes are cooling, make the frosting:

In a glass measuring cup, heat the chocolate in the microwave in
30-second increments until it's almost completely melted (this took
three 30-second zaps), then stir until it is smooth, and pour it into
the bowl of a stand mixer to cool for a couple of minutes.

Using the whisk beater on your mixer, slowly whisk the cream into
the cooled chocolate. Beat on medium speed and add the butter, Splenda,
cocoa, vanilla and chocolate extract or coffee. Beat until smooth and
fluffy, approximately 3 minutes.

If you want to spread the frosting with a palette knife, you can do
it now. If you want to pipe it through a pastry bag (or in a zip-loc
bag with one corner snipped off), fill your pastry bag. If it doesn't
pipe easily, put the pastry bag into the refrigerator for 20-30 minutes
so the icing can stiffen up a bit. (I found it easy to pipe right away,
without chilling it.)

These cupcakes don't keep well, so serve them the same day you make them.